Re: [osg-users] Advice sought for rendering coins in OSG. Lots of coins.
Hi Christian, To profile the peformance bottleneck it would be best to press 's' a couple more times to get the full frame rate stats so you can see exactly which parts of rendering are the bottleneck - the frame rate only tells that you frame rate is reducing it doesn't give any clues to why. In terms of optimizing performance I'd be inclined towards trying out using draw instanced support. Not all cards support this, but it would help with draw lots of identical geometry with the only different being it's position in space. Robert. On Sun, Jun 21, 2009 at 1:25 AM, Christian Buchnerchristian.buch...@gmail.com wrote: A little youtube video clip showing the progress on my coin pusher arcade prototype with very simple graphics: http://www.youtube.com/watch?v=ubpZUTuO1ecfmt=22 The bottleneck here is definitely physics. Frame rates take a dip when lots of coins are interacting. I am hoping for some public CUDA support in the Bullet physics library in the near future. This demo is based mainly on the osgbullet source code found on the OSG Wiki. I replaced the golf ball in the demo with coins and I am tossing in a new coin every second. I also added a box-shaped pusher and a (yet invisible) rear wall that makes sure the coins fall off the pusher eventually. Christian ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Advice sought for rendering coins in OSG. Lots of coins.
Christian Buchner wrote: The bottleneck here is definitely physics. Frame rates take a dip when lots of coins are interacting. I am hoping for some public CUDA support in the Bullet physics library in the near future. My source inside Bullet development indicates that fully functional public Cuda solver is still some time off, perhaps 6 months or so. I assume you're using cylinder collisions shapes? I have not played with them very much. I get excellent performance from bullet with several dozen boxes interacting, but performance slows to a crawl as soon as I add a single convex hull into the mix. I'm looking at running the physics sim in a separate thread so that the app maintains framerate and interactivity, but unless I do something to simplify the simulation, the visual results will still appear sluggish in spite of the high frame rate. -Paul ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Advice sought for rendering coins in OSG. Lots of coins.
To profile the peformance bottleneck it would be best to press 's' a couple more times to get the full frame rate stats so you can see exactly which parts of rendering are the bottleneck - the frame rate only tells that you frame rate is reducing it doesn't give any clues to why. I am pretty sure I am limited by the physics. Right now I have to reduce the physics time step dynamically to stay within my tolerated frame rate window. A final video (I promise!) is posted here and it shows an almost complete pusher machine and up to 400 coins in the game. http://www.youtube.com/watch?v=0bLAq7btZbUfmt=22 I have since made the pusher operate faster so the player won't fall asleep. I still have to add the game mechanics (player's coin balance, player controlled coin insertion etc). My coins are currently rendered several OSG PositionAttitudeTransforms, all from the same model instance. I may switch to an approach that uses vertex shaders soon. A future enhancement could put the physics on a separate thread from OSG. We will see how that goes. Christian ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Advice sought for rendering coins in OSG. Lots of coins.
A little youtube video clip showing the progress on my coin pusher arcade prototype with very simple graphics: http://www.youtube.com/watch?v=ubpZUTuO1ecfmt=22 The bottleneck here is definitely physics. Frame rates take a dip when lots of coins are interacting. I am hoping for some public CUDA support in the Bullet physics library in the near future. This demo is based mainly on the osgbullet source code found on the OSG Wiki. I replaced the golf ball in the demo with coins and I am tossing in a new coin every second. I also added a box-shaped pusher and a (yet invisible) rear wall that makes sure the coins fall off the pusher eventually. Christian ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Advice sought for rendering coins in OSG. Lots of coins.
Hi Christian, Out of interest are you simulating a penny push machine? I had the same idea for a hobby project a while back. It's a great idea, although it might be tricky to get the physics working nicely. Unfortunately my ponderings stop there as I never found the time to get on it. However, with regards to glsl effects you wanted, try these two pages http://www.typhoonlabs.com/tutorials/glsl/Chapter_4.pdf http://www.ozone3d.net/tutorials/index_glsl.php They give good explanations and glsl implementations. Getting the shaders to work with the OSG will be trivial. Personally I wouldn't set the Intel GMA chipset as your minimum spec. You'll be making life difficult for yourself just to accommodate hardware that makes a half arsed attempt to offer hardware accelerated 3D. ( Just my 2p ;) ) Hope that helps a little. Kim. -Original Message- From: osg-users-boun...@lists.openscenegraph.org [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Christian Buchner Sent: 22 May 2009 11:57 To: OpenSceneGraph Users Subject: [osg-users] Advice sought for rendering coins in OSG. Lots of coins. Hi, I was going to start a hobby (i.e. noncommercial) project to simulate an electromechanical coin arcade game. This would include rendering potentially hundres of coins that physically interact (think 500...1000 coins). For the physics simulation I am going for the free bullet physics package. For rendering I intend to use OSG. One problem with GPUs is that round shapes map badly to triangle meshes. One needs a lot of triangles to make the coins appear sufficiently round. Lots of vertices may conflict with the idea of rendering many coins simultaneously. I could go down the route of using a mesh based 3D model combined with LOD techniques. However this may incur some performance issues on architectures like Intel GMA that have pixel shaders in hardware but do all their vertex processing on the CPU. Also I would really like to include a 3D relief for the coin imprinting (embossment), either by using simple bump mapping or more advanced pixel shader based techniques like parallax mapping or relief mapping. To get simulated (fake) reflections I need to apply some kind of environment mapping. Considering that I will have to use pixels shaders anyway, I was thinking that this can a pixel shader could just as well be used to also render a geometric primitive like for example a cylinder. The pixel shader would have to do some calculatios like does the view ray intersect with the primitive? and what is the surface normal?... very much like in raytracing. The only vertex based geometry needed would be a billboard that fully covers the visible extents of the geometric primitive (or alternatively a box that wraps around the visible extents of the primitive) To get started with this I could use a few pointers and suggestions. 1) Does anyone here know some open sourced OSG based code that renders primitives like spheres, cylinders, cones or the like within a GLSL pixel shader? I know there have been projects in academia that did just this, but is there anything open sourced? 2) Would anyone know a nicely done (in terms of documentation, clarity) parallax mapping or relief mapping implementation in GLSL and OSG? I've found a lot of conference papers on this (Siggraph etc) but almost no source code. It's often 10 times harder to start something from scratch than to modify someone's existing code. So thanks a lot for any pointers and help, Christian ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.or g* To view the terms under which this email is distributed, please go to http://www.hull.ac.uk/legal/email_disclaimer.html *___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Advice sought for rendering coins in OSG. Lots of coins.
Out of interest are you simulating a penny push machine? Yes. These sucked the life out of my wallet on my last trip to Shanghai and Hangzhou. Playing with virtual currency would be cheaper. ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Advice sought for rendering coins in OSG. Lots of coins.
You could take a look at the draw instanced support in OSG, good for drawing lots of things. BRDFs could be used to render a high fidelity coin on just a couple triangles without the flat, wallpaper-like effect of a regular texture map. The first edition orange book included a section on implementing BRDFs in shaders. I haven't seen much discussion on BRDFs lately, perhaps because generating them is so complex. Paul Martz Skew Matrix Software LLC http://www.skew-matrix.com +1 303 859 9466 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Advice sought for rendering coins in OSG. Lots of coins.
You could take a look at the draw instanced support in OSG, good for drawing lots of things. I believe this instancing capability might require Geforce 8 class hardware. I was thinking along the lines of how the osgforest sample replicates thousands of trees from the same billboard drawable. However I would also need to add per instance rotation, not jus a simple displacement. BRDFs could be used to render a high fidelity coin on just a couple I think BRDFs are a little over my head. I think they would not add a true relief, just different reflectivity at different locations on the coin surface. Christian ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Advice sought for rendering coins in OSG. Lots of coins.
Hi, I would use osgparticle. You can induce rotations displacement. HTH Sylvain Christian Buchner wrote: You could take a look at the draw instanced support in OSG, good for drawing lots of things. I believe this instancing capability might require Geforce 8 class hardware. I was thinking along the lines of how the osgforest sample replicates thousands of trees from the same billboard drawable. However I would also need to add per instance rotation, not jus a simple displacement. BRDFs could be used to render a high fidelity coin on just a couple I think BRDFs are a little over my head. I think they would not add a true relief, just different reflectivity at different locations on the coin surface. Christian ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org -- Sylvain Cormier Technologist/Test Manager Société des arts technologiques Propulse[art] 514 804 8434 1197 boulevard Saint-Laurent C.P. 1083 Succursale Desjardins Montréal (Québec) H5B 1C2 Canada ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Advice sought for rendering coins in OSG. Lots of coins.
Out of interest are you simulating a penny push machine? Here is a first youtube video of my progress so far. http://www.youtube.com/watch?v=74C61A-wzaA This is based on the osgBullet sample code found on the OpenSceneGraph Wiki on Support/Tutorials. A few things to note: - No shiny coins with imprint yet, just a simple cylindrical model exported from Blender. - things get slow with more than 70 coins on this (slightly outdated) machine. The bottleneck is definitely physics, not rendering. May have to experiment with CUDA acceleration to achieve 500 coins and more. - The coins slide apart when stacked on top, as if the whole setup was on a vibrating ground plate. I need to get in touch with the guys on the bullet physics forums to see if this can be solved. I will be back when I've got the shiny coins done... and hundreds of them! Thanks for all your suggestions so far. Christian ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
